A central problem in motor control research is to characterize the changes of internal representations for action planning that occur with skill learning. Traditional behavioral measures of performance such as improving reaction time or accuracy establish that a skill is being learned but do not sufficiently characterize the internal processes that lead to an improvement. The first goal of the current proposal is to use specific kinematic measures of performance to characterize brain behavior relationships underlying learning. For continuous tracking we have developed a model for estimating the contribution of position, velocity and acceleration estimates of a hidden movement trajectory with measured performance using canonical correlation. These will be used to model changes in the brain during skill acquisition [unreadable] [unreadable] Specific Aim 1: Characterize the internal representation of a continuous motor skill as a function of feedback and control mechanisms. [unreadable] [unreadable] Specific Aim 2: Identify convergence of functional anatomy. It is hypothesized that with sufficient training there will be a convergence in the neural systems used to control a movement, irrespective of the differences in training. [unreadable] [unreadable] Specific Aim 3: Determine changes in functional anatomy with progression/regression of skill. How do control parameters change with distraction, fatigue or a change of task demands? [unreadable] [unreadable] These aims relate fundamental aspects of normal motor learning and underlying functional anatomy. The experiments demanding extensive practice are particularly relevant for developing rational pathophysiologic models of brain plasticity that are applicable to studies of functional recovery after stroke. [unreadable] [unreadable]